Priming and straining device for screw and centrifugal pumps



Nov. 20 1923. 1,474,449

7 A. B. SEABORNE PRIMING AND STRAINING DEVICE FOR SCREW AND CENTRIFUGAL PUMPS Filed June '7, 1925 INVENTOR.

NOV. 20, 2

LEVER BURTON SEABORNE, OF LONDON, ENGLAND.

Application filed June 7,

T all whom it may concem:

Be it known that I, ALLEVER BURTON SEABORNE, a subject of the King of Great Britain, residin at Eastwood, Ballards Lane, North Finchley, London, En land, have invented Improvements in and elat ing to Priming and Straining Devices for Screw and Centrifugal Pumps (for which I have filed an application in Great Britain May 18, 1922, #14918), of which the following is a specification.

The invention relates to improvements in priming and straining devices for screw and centrifugal pumps and has for its primary object ensuring such non-positive acting pumps always starting up and continuing in operation. In such types of pump it has been proposed to arrange an interceptor or tank connected to the suction side of the pump which is primarily filled with liquid and kept partly filled whilst the pump is in operation, but it is found that after a certain period owing to accumulation of air in the upper part of the interceptor or tank, derived from the fluid pumped, that the pump will sto through the air displacing the liquid in t e pum casing and in order to try and overcome t is defect it has been proposed to insert a valved by pass pipe between the top of the interceptor or tank and the rising main or delivery pipe of the pump. According to the present invention the difficulty of getting rid of, the air in the interceptor or tank is not only efl'ectually .overcome but the liquid before entering the pump is effectually strained so reventing the pump from becoming choke which is of the utmost importance when dealing with sewage and like waters.

The presentv invention comprises essentially means for automatically straining the liquid to be pumped, and ejecting the air from the interceptor or priming tank through the pump during its operation.

This invention will now be more particularly described making reference to the accompanying drawing in which Fig. 1 is a'broken view in end elevationartly in section-of a centrifugal pump fitted with an interceptor embodying the present invention. 7

Fig. 2 is a sectional view in side, elevation of a modified form of interceptor, and

Figs. 3 and 4 are similar views of further modifications.

i ENG STEMNING DEVICE FOE SCREW AND CENTBIFUGAL PUMPS.

1923. Serial No. 643,981.

Throughout the views similar parts are marked with like letters of reference.

A simple and convenient embodiment of this invention where it is not required to finely strain the liquid but only to prevent relatively large pieces of foreignmatter entering the pump is that illustrated in Fig. l in which is employed a closed interceptor or tank a of any convenient shape or cross section and of such a capacity as to contain the rarefied air that obtains on starting a pump against an empty suction pipe as well as suflicient liquid for efficiently priming the pump. This tank a is connected to the suction pipe or in communication with the suction side of the pump in such position that its contents are mostly above the level of the top of the pump casing. The

suction pipe 6 is connected to the top of the tank a: and the suction pipe I) to the pump 1] is connected to the bottom of the tank a so that all liquid passes through the tank before entering the pump a? and being delivered to the outlet or rising maind. Within the tank a is arranged a tube c-preferably a coned tube shaped and arranged as shown-the bore of which is in line with the entrance to the tank and the exit from it.

The upper end of this tube a terminates some distance below the entrance to the tank a and its bottom end is in close proximity to the exit from the tank, by such means it will be seen that any relatively large pieces of foreign matter are prevented from entering the suction pipe 6 of the pump. The tube 0 is held in proper position within the tank in any convenient manner, for instance by webs or a spider attached both to the tube and tank. p

The whole arrangement is such that when the pump d is in operation any air contained in the liquid and accumulating in the upper part of the tank a is ejected together with the liquid throughthe pump d.

In the modification shown in Fig. 2 instead of a single tube c within the tank a, a plurality of tubes cof relatively small bore or cross section are employed in which case the upper ends of said tubes 0 ,-which tubes may be relatively short and are held closely together within the upper bell mouthed end of the pipe c--are preferably either bevelled oil or their outer ends arranged in a cone like formation, in order that any solid matter or dbris in the liquid pumped, is automatically diverted from entering the said tubes and so prevented from reaching the pump. One or more hand holes a, provided with removable covers a may be provided in the tank to enable solid iatter ondbris to be readily removed from its interior.

Instead of employing a series of tubes 0 within the tube 0, the latter may be provided with a perforated cone shaped mouth or as shown in Fig. 3, the'tube a may be provided with a plurality of strips or bars 0 so arranged as to provide interstices or passages for the liquid and air to throng the tube 0. in some cases a perforated grid 6 may be arranged around the lower end of the tube 0 so as to prevent any foreign matter rejected by the upper part of the tube a entering the suction pipe 5 through the space between its entry end and the exit end of the tube 0.

In the modification shown in Fig. 42, instead of arranging a plurality of tubes or strips within the mouth of the tube 0, the latter may be dispensed with and a spirally coiled sheet or" metal 0 may be employed. The spirally arranged sheet is so coiled as to allow spaces between the convolutions. to allow for the water and air passing therethrough to the pump Whilst preventing the passa e of foreign matter. As a further modi cation, a length of relatively narrow width strip metal or material may be coiled spirally as described and inserted within the mouth of the tube 0.

The action of the interceptor in operation is the same in all cases and is as follows ihe interceptor or tank a having been primarily filled with li uid, on starting up the pump cl, liquid is rst drawn through the suction pipe I) from the tank (1, thus inf/ante creating a negative pressure within it which causes the liquid to rise in the suction pipe Z) and flow into the tank a. T he incoming liquid catches and entrains the rarefied air contained in the upper part of the tank and conveys it through the pump (Z into the dclivery or rising main d ll deciare that what I claim and desire to secure by Letters Patent is 1. A priming and straining device for cen trifuga-l and like pumps L'OIHPl'lS'lIIg an interceptor or priming tank arranged between the suction pipe and the pump so that its contents are mostly above the level of the top of the pump casing and an ejector and straining device within said tank so arranged that the liquid passing through the tank before entering the pump entrains the air accumulating within the tank as set forth.

2. A priming and straining device for centrifugal and like pumps comprising a closed interceptor or priming tank of such a ca pacity as to contain the rarefied air that ohtains on starting a pump against an empty suction pipe as well as suiiicient liquid for ei'iiciently' priming the pump, the said tank bein so arranged that its contents are most ly a ove the level of the top of the pump casing, an inlet at the top of said tank in communication with the suction pipe, an outlet at the bottom of said tank connected to the suction pipe of the pumpso that all liquid passes through the tank before entering the pump, and a. tube held within said tank so that its bore is in line with the inlet and outlet and the upper end of said tube terminates some distance below the inlet to the tank whilst its bottom end is in close proximity to the outlet from the tank, as set forth.

ALLEVER BURTON SEABORNE.

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